The development of water-borne spray paint has created the need for the present invention. Valves for water-borne paint must be capable of maintaining separation of propellant and paint. They must also be able to thoroughly purge residue from discharge surfaces. Unlike other aerosol products, water-borne paints are not compatible with propellants in their liquefied state.
Heretofore aerosol valves either relied on mixing propellant with product, or they failed to adequately purge residue from discharge passageway surfaces. Water-borne paint residue remaining in valve discharge passageways quickly drys, clogging the valve and rendering it useless. The hydrocarbon propellants which become the primary pressurizing fluids after the ozone depletion controversy, cause coagulation within valves when mixed with water-borne paint. Mixing of other propellants with water-borne paint produces a detrimental froth.